Atrial fibrillation (“AF”) is a heart disease that affects a significant portion of the population of the United States (e.g., about 1 to 2 percent in the general population and up to about 10 percent in elderly populations). In a patient with AF, the electrical impulses that are normally generated by the sinoatrial node are overwhelmed by disorganized electrical activity in the atrial tissue, leading to an irregular conduction of impulses to the ventricles that generate the heartbeat. The result is an irregular heartbeat, which may be intermittent or continuous. In human populations, AF-induced irregular heartbeat is a significant source of stroke, heart failure, disability, and death.
There are a number of surgical options available for treating AF. One approach is known as the Cox-Maze III procedure. In this procedure, the left atrial appendage is excised, and a series of incisions and/or cryo- or radiofrequency-lesions are arranged in a maze-like pattern in the atria. The incisions encircle and isolate the pulmonary veins. The resulting scars block the abnormal electrical pathways, improving normal signal transmission and restoring regular heart rhythm. Less invasive techniques are also possible, which may use heating or cooling sources to create impulse-blocking lesions on the heart by ablation rather than incision.
Catheter-based radiofrequency ablation is a particularly common treatment for symptomatic AF, as it is less invasive than surgery. Whether this, or any of the foregoing treatments is used, however, there are certain drawbacks and/or limitations with known techniques. Embodiments discussed below can ameliorate, avoid, or resolve one or more of these drawbacks, as will be apparent from the present disclosure.